The Giants optioned Whisenhunt to Triple-A Sacramento on Thursday.
Whisenhunt made a spot start Wednesday in Atlanta and picked up the win, allowing two runs over five frames. The left-hander will rejoin the rotation at Sacramento, where he's collected a 3.65 ERA and 77:30 K:BB over 69 innings this season. Whisenhunt could be the first name called when the Giants need another starter again.